Scariest Rare Mental Disorders of All Time

Mental illnesses are one of the most significant causes of disability. These illnesses are due to underlying medical conditions and might get triggered due to environmental factors. Europe is the country with the highest rate of mental illnesses found in people. There are various types of mental disorders and their severity varies from person to person. Depression is the most common mental disorder, followed by anxiety. However, apart from these common neurological diseases, there are some uncommon disorders too. These are very rarely found, but they do exist. The disability that they cause to their victims is severe and it affects their lives adversely.

Let us find out what some of the weirdest mental illnesses that actually exists. Prepare to be shocked that these disease truly exists.


The name itself is self-explanatory. The disorder characterized by the unusual desire of a person to give pain to themself by eating or biting their own body parts. The most common part of the body involved in this are fingers and hands. Although this disorder is yet to be part of classification in the DSMIV, there has been cases reported about it several times now. There are case studies of such patients who were found to be eating their own fingers after nails. This condition may arise independently or in association with some other illness.


Another name for the Body Integrity Identity Disorder and Xenomelia. Apotemnophilia is a disease in which the affected individual wants to get disabled by getting his/her healthy body parts removed. This particularly refers to the limbs of the individual. It sometimes also includes the urge of getting dumb or deaf. The cause of the disorder is not yet known, and the problems get resolved after the amputation.


It is a disorder in which the affected person believes that they belongs to the Bovine family. The person behaves as one and adopts the eating habits as well. The condition is thought to be linked to suggestion and auto suggestion, which is a psychological process of guiding a person’s thought and behavior. Hypnosis is also considered to be one of the contributing factors.

The Buyid Prince of Persia (from 934-1062 BC),  Al Majd Al Dawlah was also one of the victims of the disease who behaved as a cow and desired to be killed so that he could be eaten.

Dr. StrangeLove Syndrome

Also called as Alien Hand Syndrome, this syndrome is characterized by an involuntary movement or interference of one limb while a person is doing an action. The person has no control over the hand that is affected and gets things done without intending to do. The disorder is usually found in people who have had their cerebral hemispheres separated after a neurosurgery. This causes disturbances in coordination of the two sides.  Other causes of the condition include stroke, tumor or infection. Although there is no treatment of the condition, but the symptoms can be controlled by engaging the affected limb in a grasping task. First case that came to notice was by a German psychologist, Kurt Goldstein, in the year 1908.  


Synesthesia refers to a neurological condition in which one of the senses stimulates the other unrelated sense. The condition can involve any combination of the five senses and hence has many sub-types. One of the most common combinations is hearing with vision. The individual affected can link numbers/letters with colors and appearance. The condition can pass on via genes and may run in the family. Although, no certain cause of the disorder is yet known, but it sometimes results due to head trauma, stroke or tumors.

Walking Corpse Syndrome

Also called as Nihilistic or Cotard’s Syndrome, this disorder is characterized by a belief that one’s body part is dead or doesn’t even exist. The syndrome is linked to underlying psychiatric or neurological illnesses. People with depression might also develop this disorder in later stages. Anxiety, depression, guilt and self-harm are a few common symptoms of the disease. The disease doesn’t yet have any diagnostic criteria and is usually diagnosed when other conditions are ruled out. There is no definite treatment for it yet. However, the electroconvulsive therapy is found to produce better outcomes in the affected individuals.

Kluver-Bucy Syndrome

The syndrome caused by the damage to the anterior temporal lobes of the brain is characterized by several features. The individual develops abnormality in recognizing objects. There is a loss of emotional expressions like anger and fear, dementia and sometimes seizures. The person’s sexual behavior also gets disturbed which makes him desire sex with non-living objects. Some rare causes of the syndrome are head injury and space occupying lesions. There is no such treatment of the syndrome itself however, psychotropic drugs can be used for symptomatic treatment.

Alice in Wonderland Syndrome

Todd’s Syndrome (named after the British Psychiatrist who diagnosed the disorder) is a very rare disorder which causes distorted perception of the surroundings or one own self. Just like the story it is named after, the syndrome makes the person feel either too small or too large as compared to the surroundings. Not only this, the person can perceive things that are closer to them, being too far and vice versa. There is involvement of a few senses like vision, touch and hearing. Distortion of size, texture and sound are a few characteristics of the disease. Some people also complain of headache particularly migraine. It might be associated with infections, migraines, tumors or stroke.

Capgras Delusion

A rare disorder that is mostly found in people with underlying neurological condition like epilepsy, memory loss or other psychiatric illnesses. The victim of the disease has a belief that someone fraudulent or fake has taken the place of people around him. The person considers the people he knows, to be imposters who intend to harm him in some way. There have been cases where the patients doubted their spouses or even siblings and parents to be the imposters who wanted to kill them. Treatment involves psychotherapy and anti-psychotic medications.

Clinical Lycanthropy

Delusional Misidentification Syndrome is another name for Clinical Lycanthropy. This is a disorder like Boanthropy, in which the affected person believes that he/she is an animal. Unlike Boanthropy, the animal associated doesn’t particularly belong to the Bovine family but rather can be an animal of any kind. The person adopts the lifestyle and habits of the animal he believes he has turned into. They also start to make sounds like that particular animal. One of the most common animals that the people think they have turned into is wolf. The syndrome is usually found in people with underlying neurological of psychiatric illness.

Foreign Accent Syndrome

A disorder characterized by a change in a person’s speech-pronunciation and placement of words, such that it seems that he/she has started to use any other language. The disease is caused by an injury to the brain, to or near the speech cortex. This alters the speech in terms of pronunciation, addition of incomprehensible words, subtraction of supporting words etc. One of the treatments offered for the disease is Speech therapy. The person is taught to move lips and tongue in a proper way and the placement of jaw is taught. Counseling has also played a significant role in helping the patients recover from the disorder. 

Jumping Frenchmen of Maine

It is an exaggerated reflex reaction to a normal stimulus like sound or light. The disorder was first identified in Maine and Quebec in the late 19th century. The affected person tends to scream, jump, throw away things as a response to any unexpected stimulus. Repeating the same words or imitating some gestures or movements involuntarily. The exact cause of the disorder is unknown. Kokk disease and Tourette syndrome are two of the related disorders. Unfortunately, the condition is not treatable and can get aggravated by some triggers like anxiety and stress. However, the symptoms tend to get milder with growing age.


An eating disorder in which there is a practice or urge of eating things that are non-food such as hair, dirt, soap etc. There is no such diagnostic test for Pica and it is diagnosed on the basis of history and examination only. The condition is most commonly due to low level of minerals in the body, primarily Iron. Iron and other supplements are given to treat the condition. It can affect people of any age and gender and is usually found in low socioeconomic areas of developing countries.


The disorder of not being able to take decisions or getting excessively anxious and worried while taking little decisions is Aboulomania. The person feels that he/she is not capable enough to go for the right decision related to a matter. A damage to the prefrontal cortex of the brain might result in the disease. Another factor that might play a role in the development of the disorder is being pampered or dictated a lot during childhood. This results in inability of the person to take decisions on his own with confidence. Even the decision of going for a shower or not is difficult for the affected person. The person loses self trust and confidence and thinks that he always needs someone to support him. This also leads to them being misused by people they depend upon. Counselling the individual helps in such cases.

Reduplicative Amnesia

Arnold Pick diagnosed the disorder in one of his patients in the year 1903. This disorder is usually found in patients with underlying neurological disease. The person affected believes that one place exists simultaneously at two places. Reduplicative Amnesia resembles to Capgras syndrome, in which the patient thinks that a person exists in two forms. Patients with brain injuries in right cerebral hemisphere and frontal lobes are found to be more affected by the disorder.

Stendhal Syndrome

Also known as the Florence Syndrome, named after the place, visited by the author Marie Henri who experienced the syndrome himself while his visit to Florence. The disorder occurs in people who get overwhelmed by the beauty in their surroundings, like in an art gallery or at a natural tourist spot and face symptoms like confusion, anxiety, palpitations and sometimes syncope.


It is a disorder in which the person performs sexual activities while sleeping. This can be alone or with a partner. These are observed to be associated with other preexisting mental condition particularly other sleep disorders. The person doesn’t seem to remember the activities he did. There have been cases of rape associated with the disorder.

Factitious Disorder

Mental illness that can happen to any one at any age, Factitious Disorder is a disease in which the sufferer acts being ill. The person goes to extents to prove that he/she is sick and needs treatment. These people do not believe the proofs that are against them or which show that they are healthy and disease free. The person tends to stay in hospitals for long and presents with a vague history of symptoms. The patient prefers to stay at hospital and receive treatments. They get transferred from one hospital to another hospital without having any medical evidence of disease.

Genital Retraction Syndrome

Genital Retraction syndrome is also known as the Koro Syndrome. It is known to be more prevalent in Asian population. The victim believes that his body part/s (mostly the Genitals) are disappearing. The person gets anxiety attacks fearing the loss of his body parts. This condition is mostly acute and usually occur in epidemics.

Jerusalem Syndrome

The Jerusalem syndrome is not listed in the DSM IV as the underlying etiology is still unknown. It’s association with other diseases is also not yet known. The disorder came into notice by psychiatrists in Jerusalem who observed the tourists who visited the place. The syndrome can present in different ways. Some victims consider themselves as a higher religious personality, while others can hear God speaking to them. Since the cause is unknown, no treatment has been identified yet for the disease.  


Also known as the de Clérambault Disease, Erotomania is a mental disorder in which the affected individual thinks that someone (who they might have never even met) is in love with them. This person is mostly a famous personality or star. Not only this, but the person might also think that he/she is in relationship with the other person. The delusion that they have, is so strong, that they fail to accept the proofs given to them against it.

This disorder can arise independently or with any other mental disease like Schizophrenia.

Medical Students’ Syndrome

Also called the Second Year Syndrome or Intern’s Syndrome is a disorder found in medical students who experience the symptoms of the disease, they are studying. The affected individuals think that they have contracted the disease that they have been studying about. This condition is different from a Hypochondriasis.

Taijin Kyofusho

This disorder is culture specific and is found in the Japanese population. The word means the fear of interpersonal relationships. This affected person has the fear of being a cause of displeasure to other people. The cause can be anything from the body odor, appearance, clothes or way of communication.

Landau-Kleffner Syndrome

Progressive Epileptic Aphasia is a medical condition which affects children of age less than 10 years. The affected child fails to understand and comprehend familiar sounds and speech. Primarily it affects the ability to understand the language and later it might affect the child’s speaking ability. Focal motor seizures or tonic-clonic seizures can also occur. Seizures usually occur during sleep. The disorder can be diagnosed by EEG and genetic testing but the exact etiology remains unknown. Anti-convulsant and speech therapy are used for the management of the disease.

Spasmodic Dysphonia

It is a condition which is due to the contraction of the laryngeal muscles. The condition is thought to be due to a problem in the basal ganglia of the brain. The contraction is not in control of the person and causes difficulty in speaking. The person might not be able to speak at all or speaks with multiple pauses which gets difficult to understand. However, types of expressive speech like shouting or singing might remain normal. Speech therapy and Botox injections have shown benefit in these cases.

This is also somewhat related to the social phobia, where a person hesitates from interacting with people. The affected person might also have the history of being very shy in his childhood.